108 lines
4.1 KiB
Groff
108 lines
4.1 KiB
Groff
.\" Copyright (c) 1996 John Birrell <jb@cimlogic.com.au>.
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by John Birrell.
|
|
.\" 4. Neither the name of the author nor the names of any co-contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd April 4, 1996
|
|
.Dt PTHREAD_KEY_CREATE 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm pthread_key_create
|
|
.Nd thread-specific data key creation
|
|
.Sh LIBRARY
|
|
.Lb libc_r
|
|
.Sh SYNOPSIS
|
|
.In pthread.h
|
|
.Ft int
|
|
.Fn pthread_key_create "pthread_key_t *key" "void (*destructor)(void *)"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn pthread_key_create
|
|
function creates a thread-specific data key visible to all threads in the
|
|
process.
|
|
Key values provided by
|
|
.Fn pthread_key_create
|
|
are opaque objects used to locate thread-specific data.
|
|
Although the same
|
|
key value may be used by different threads, the values bound to the key
|
|
by
|
|
.Fn pthread_setspecific
|
|
are maintained on a per-thread basis and persist for the life of the calling
|
|
thread.
|
|
.Pp
|
|
Upon key creation, the value NULL is associated with the new key in all
|
|
active threads.
|
|
Upon thread creation, the value NULL is associated with all
|
|
defined keys in the new thread.
|
|
.Pp
|
|
An optional destructor function may be associated with each key value.
|
|
At
|
|
thread exit, if a key value has a non-NULL destructor pointer, and the
|
|
thread has a non-NULL value associated with the key, the function pointed
|
|
to is called with the current associated value as its sole argument.
|
|
The
|
|
order of destructor calls is unspecified if more than one destructor exists
|
|
for a thread when it exits.
|
|
.Pp
|
|
If, after all the destructors have been called for all non-NULL values
|
|
with associated destructors, there are still some non-NULL values with
|
|
associated destructors, then the process is repeated.
|
|
If, after at least
|
|
[PTHREAD_DESTRUCTOR_ITERATIONS] iterations of destructor calls for
|
|
outstanding non-NULL values, there are still some non-NULL values with
|
|
associated destructors, the implementation stops calling destructors.
|
|
.Sh RETURN VALUES
|
|
If successful, the
|
|
.Fn pthread_key_create
|
|
function will store the newly created key value at the location specified by
|
|
.Fa key
|
|
and returns zero.
|
|
Otherwise an error number will be returned to indicate
|
|
the error.
|
|
.Sh ERRORS
|
|
.Fn pthread_key_create
|
|
will fail if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EAGAIN
|
|
The system lacked the necessary resources to create another thread-specific
|
|
data key, or the system-imposed limit on the total number of keys per process
|
|
[PTHREAD_KEYS_MAX] would be exceeded.
|
|
.It Bq Er ENOMEM
|
|
Insufficient memory exists to create the key.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr pthread_getspecific 3 ,
|
|
.Xr pthread_key_delete 3 ,
|
|
.Xr pthread_setspecific 3
|
|
.Sh STANDARDS
|
|
.Fn pthread_key_create
|
|
conforms to
|
|
.St -p1003.1-96 .
|